A high-latitude fauna of mid-Mesozoic mammals from Yakutia, Russia.

Alexander Averianov,Rico Schellhorn,Alexey Lopatin,Pavel Skutschas,Petr Kolosov,Thomas Martin,Dmitry Vitenko,Anthony Fiorillo

doi:10.1371/journal.pone.0199983

Alexander Averianov, Rico Schellhorn + Show 6 more

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https://doi.org/10.1371/journal.pone.0199983

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Abstract

The Early Cretaceous (?Berriasian-Barremian) Teete vertebrate locality in Western Yakutia, East Siberia, Russia, has produced mammal remains that are attributed to three taxa: Eleutherodontidae indet. cf. Sineleutherus sp. (Haramiyida; an upper molariform tooth), Khorotherium yakutensis gen. et sp. nov. (Tegotheriidae, Docodonta; maxillary fragment with three molariform teeth and dentary fragment with one molariform tooth), and Sangarotherium aquilonium gen. et sp. nov. (Eutriconodonta incertae sedis; dentary fragment with one erupted molariform tooth and one tooth in crypt). This is the second occurrence of Mesozoic mammals in high latitudes (paleolatitude estimate N 63–70°) of the Northern Hemisphere. In spite of the presumed Early Cretaceous age based on freshwater mollusks, the Teete mammal assemblage has a distinctive Jurassic appearance, being most similar to the Middle-Late Jurassic mammal assemblages known from Siberia, Russia and Xinjiang, China. The smooth transition from Jurassic to Cretaceous biota in Northern Asia is best explained by stable environmental conditions.

Highlights

The recent decades witnessed a tremendous progress in the study of Mesozoic mammals [1, 2]
The metatherians, and eutherians from the Colville River vertebrate assemblage resemble those from the Maastrichtian sites in Wyoming, Montana (USA) and Alberta (Canada) but are different on the species level, while the multituberculates are represented by discrete taxa [50, 52]
The Colville River vertebrate assemblage is remarkable in the lack of amphibians and non-dinosaurian sauropsids, such as turtles, squamates, and crocodyliforms

Summary

Introduction

The recent decades witnessed a tremendous progress in the study of Mesozoic mammals [1, 2]. The base of the section at the Teete locality is comprised of green silts with randomly dispersed shell fragments of bivalves and gastropods (Fig 3). The pollen assemblage collected from the Teete sections contains typical Neocomian (Lower Cretaceous) taxa with some Late Jurassic elements [9].

Results

Conclusion